Metro Exodus

Their are 10 ranged weapons in the game. The list is in order of when they can be picked up.

Kalash (ak47)- Can be found as early as the MOSCOW level and commonly found in VOLGA.

Revolver- Can be found as early as the MOSCOW level and commonly found in VOLGA.

Bastard- Can be found across the VOLGA level, mostly carried by bandits.

Ashot- Single round shotgun, Can be found commonly in the VOLGA level on enemies. Mostly found with a double barrel attachment on them.

Tikhar- Pneumatic weapon that shoots ball bearings. Can be found inside the Aurora next to the crafting bench. Tokarev will most likely give it to you when he will ask to chat with you while on the level VOLGA. You might have to do some missions first and come back later for it to spawn.

Gatlin- Found on the YAMANTAU level. While progressing through the story level you'll come across someone carrying this. Can't miss them. Their will be other opportunities in the CASPIAN level to grab this from the heavy armoured enemies that attack you in the natural story path.

Shambler- Semi-auto shotgun. Automatically used in the intro of the game but in case you didn't get a kill with it the next time you can get it is in the CASPIAN level. Following the story path you'll get the moral choice to kill or knock someone out. After you've done that he will drop the shambler.

Valve- Sniper rifle, can be found in the CASPIAN level. Found on some of the bandits and found on the crane tower that your companion tells you to check out.

Bulldog rifle- Found on the CASPIAN level on one of the bandits attacking the Lighthouse. You'll need to go here while following the story path. And can be found on one of the guards while taking the water tanker in the Oasis.

Crossbow (Helsing)- Found in the Beginning of the TAIGA level. You will automatically pick this up.

If you would like to know what the weapons above look like, here is a link to the official metro site with pictures:
https://www.metrothegame.com/game/weapons/

You won't be able to get this achievement until the start of the TAIGA level.

You need to get at least one kill (human or monster/animal) with each of the game's ranged weapons - that's Shambler shotgun (the gun you have during the intro, so you will have gotten a kill with it then), Revolver, which is given to you by Ermak in the MOSCOW mission and will then be common throughout the game, Kalash assault rifle (an AK-74, easily the most common weapon in the game), Bastard SMG (more common in the first two missions), Ashot shotgun (single-barrel shotgun that can be upgraded to, and is often encountered as, a double-barrel, but is still the same weapon so a kill with either version would work), which is found throughout the first 4 levels, Tikhar pneumatic rifle (so you need to pump it with air by holding X and pressing RT manually if you want it to deal maximum damage), which will be given to you by Tokarev on the train and cannot be picked up normally, the Gatling LMG (you will get one at the end of Yamantau level, when you have to fight an armored mook armed with one of these - burn him with a couple of Molotovs and take his gun - you will have an opportunity to use it almost immediately afterwards) - bear in mind that you need to wind it up manually (by first holding X with it equipped and pumping RT) like a pneumatic weapon if you want the best results, Bulldog assault rifle (a modern version of Kalash), which won't appear until the CASPIAN level, Valve sniper rifle (again, most common in CASPIAN though you might find one earlier than that), and, lastly, the Crossbow (the game sometimes refers to it as "Helsing", even though that is a different gun that is not in this game - you can find an upgrade that effectively turns one into Helsing by adding a pneumatic system, but otherwise it's just a crossbow) which will be your main weapon during the TAIGA level (you will find one attached to the back of a statue shortly after you are fished out a river - use it to kill a wolf just down the road and the achievement should pop).

In this video guide I will be showing you every weapon you need to get a kill with to get the achievement. Now for the ones at the beginning of the game are revolver and the shambler in the level MOSCOW. In the VOLGA level are the kalash, ashot, bastard smg, and the tikhar can be found on the train. Now most of these guns can be found on enemies or by looting. The gatling gun is on the YAMANTAU level. You will kill a heavy for it. The bulldog and the valve are on the CASPIAN level. You will find these on enemies or by looting also. The last gun you will get is the crossbow which is on the level TAIGA at the beginning on the statue.

This guide is for anyone having trouble getting this to unlock. Try removing attachments from the guns and then getting a kill. I finished my playthrough and KNEW for a fact that I had gotten multiple kills with each gun. I started NG+ and activated "my guns". On the Volga level I switched to each gun and got multiple kills with each and STILL no achievement. I then tried getting a kill with each gun without any fancy attachments. The achievement popped when I got a kill with the Ashot (setup as a single shot). Every other time I used that gun I had the quad barrel attached. Hope this helps anyone who is stuck